Science
Mechanism of Action
This ingredient functions solely as a colorant, providing a black hue to the material it is incorporated into.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Direct Black 51 demonstrates sensitivity to strong hydrochloric acid, leading to a color shift from violet black to purplish red and subsequent precipitation. Its color can also be influenced by the presence of copper and iron ions.
Conflicts
- strong acids
- copper ions
- iron ions
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) has not conducted a specific safety assessment for Direct Black 51. Regulatory information is conflicting; while EWG Skin Deep indicates 'Violation of government restrictions' and 'HIGH Use Restrictions' from the EU Cosmetics Directive, official EU bans for CI 27720 were not definitively located. Conversely, the Personal Care Products Council suggests it is 'Determined safe for use in cosmetics, subject to concentration or use limitations'. FDA status remains unknown. EWG Skin Deep rates it 'LOW' for allergies and immunotoxicity and 'LOW' for developmental and reproductive toxicity, but 'LOW_MODERATE' for cancer risk. Concerns arise from other chemically related benzidine-based dyes, which have demonstrated carcinogenic properties, highlighting the need for a thorough official safety assessment for Direct Black 51.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Given the lack of comprehensive safety review by authoritative bodies and conflicting regulatory information, alongside potential concerns regarding carcinogenicity, Direct Black 51 is not recommended for precision skincare formulations.
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References
Sources